What is even more horrifying than this little scene from Alcatraz is that the toilet is located directly across from the cell on the other side. If I recall correctly they aren’t even offset, so when you had to go, privacy was out of the question. That thought alone would keep me on the straight and narrow.
The vent at the back was the way a few clever inmates escaped. They gradually chipped away at it with sharpened spoons from the kitchen. At the same time they starved themselves to lose as much weight as possible and then…
I am reasonably sure that The Shawshank Redemption was inspired by that event.